Custody

If I’m only 18, (19 in May) would I be able to get custody of my 14 year old brother? My moms got tons of problems with drugs and alcohol right now and isn’t even home half the time, and then she is verbally and sometimes physically abusive to both my brothers (my 16 year old brother would go to live at my grandmas). And we only see our dad maybe once a month, and he’s also extremely into drugs and alcohol, so he wouldn’t be an option for him to go to either, and the rest of our family would definitely not take him either. I’m getting an apartment at the end of the month so I’d be able to have a room for him.